Scalable port range management for security policies

ABSTRACT

Techniques are disclosed for implementing scalable port range policies across a plurality of categories that support application workloads. In one example, a policy agent receives, from a centralized controller for a computer network, a plurality of policies. Each policy of the plurality of policies includes one or more policy rules, and each of the one or more policy rules specifies one or more tags specifying one or more dimensions for application workloads executed by the one or more computing devices and a corresponding port range. The policy agent assigns, based on a policy rule, a port range specified by the policy rule to objects of the one or more computing devices that belong to categories described by the one or more dimensions of the one or more tags of the policy rule. The categories support the application workloads and are assigned to the tags by a centralized controller.

This application is a divisional of U.S. application Ser. No. 16/023,978which was filed on Jun. 29, 2018, the entire content of which isincorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to computer networks, and morespecifically, to distributed applications.

BACKGROUND

Virtualized data centers are becoming a core foundation of the moderninformation technology (IT) infrastructure. In particular, modern datacenters have extensively utilized virtualized environments in whichvirtual hosts, such virtual machines or containers, are deployed andexecuted on an underlying compute platform of physical computingdevices.

Virtualization with large scale data centers can provide severaladvantages. One advantage is that virtualization can provide significantimprovements to efficiency. As the underlying physical computing devices(i.e., servers) have become increasingly powerful with the advent ofmulticore microprocessor architectures with a large number of cores perphysical CPU, virtualization becomes easier and more efficient. A secondadvantage is that virtualization provides significant control over theinfrastructure. As physical computing resources become fungibleresources, such as in a cloud-based computing environment, provisioningand management of the compute infrastructure becomes easier. Thus,enterprise IT staff often prefer virtualized compute clusters in datacenters for their management advantages in addition to the efficiencyand increased return on investment (ROI) that virtualization provides.

SUMMARY

In general, the disclosure describes techniques for a scalable,multi-dimensional policy framework to support flexible application ofpolicies for controlling network traffic among workloads executingwithin a computing environment and that may be categorized along anumber of different dimensions. Such categories may includeapplications, deployments, application tiers, geographic sites, virtualnetworks, virtual machines, interfaces, projects, security requirements,quality requirements, users, or compliance requirements, for example.Each type of such category represents a dimension for workloads thatgenerate or consume network traffic. In some examples, the policyframework described herein permits a centralized controller to definetags for objects that execute or otherwise enable workloads withspecific dimensions across multiple levels. Example levels of suchobjects include a global environment level, a project level, a virtualnetwork level, a virtual machine level, and an interface level. In oneexample, tags map security requirements for the objects.

Policies may then be expressed along multiple dimensions in terms oftags corresponding to categories to which the objects belong. Asdescribed herein, a policy defines one or more policy rules. Each policyrule specifies one or more tags and one or more port ranges assigned toobjects that belong to categories described the one or more tags.Distributed policy agents executing on computing devices that host theworkloads may then apply the policies to objects that belong tocategories described by one or more dimensions of a tag of a givenpolicy rule to assign one or more port ranges of the given rule to theobject. Further, a policy agent may identify, based on one or more portranges of a given policy rule, an object that belongs to categoriesdescribed by a tag of the given policy rule as associated with a networktraffic flow. The policy agent may apply, to the network traffic flow,an object-specific firewall policy that corresponds to the identifiedobject to permit or block the network traffic flow. At least in somecases, the policy agents apply the policies at the interface level. Inthis way, a user or administrator may define simplified, object-specificfirewall policies, rather than defining firewall policies for a portrange that are agnostic to the objects that actually make use of theport range. Such policies are scalable and robust across many differenttypes of deployments and execution environments.

In one example, this disclosure describes a method comprising:receiving, by a policy agent of one or more computing devices and from acentralized controller for a computer network, a plurality of policies,wherein each policy of the plurality of policies includes one or morepolicy rules, and wherein each policy rule of the one or more policyrules specifies one or more tags specifying one or more dimensions of aplurality of dimensions for application workloads and a correspondingport range; and for each policy rule of the one or more policy rules,assigning, by the policy agent, a port range to objects that belong tocategories of a plurality of categories described by the one or moredimensions of a tag of the policy rule, wherein the plurality ofcategories support the application workloads and are assigned to the oneor more tags, wherein the application workloads are executed by the oneor more computing devices, and wherein the one or more computing devicesinclude the plurality of categories.

In another example, this disclosure describes a policy agent for one ormore computing devices, configured to: receive, from a centralizedcontroller for a computer network, a plurality of policies, wherein eachpolicy of the plurality of policies includes one or more policy rules,and wherein each policy rule of the one or more policy rules specifiesone or more tags specifying one or more dimensions of a plurality ofdimensions for application workloads and a corresponding port range; andfor each policy rule of the one or more policy rules, assign a portrange to objects that belong to categories of a plurality of categoriesdescribed by the one or more dimensions of a tag of the policy rule,wherein the plurality of categories support the application workloadsand are assigned to the one or more tags, wherein the applicationworkloads are executed by the one or more computing devices, and whereinthe one or more computing devices include the plurality of categories.

In another example, this disclosure describes method comprising:assigning, by a centralized controller for a computer network and to aplurality of categories that support application workloads, tagsspecifying one or more dimensions of a plurality of dimensions for theapplication workloads, wherein the application workloads are executed byone or more computing devices of the computer network, and wherein theone or more computing devices include the plurality of categories;receiving, by the centralized controller and from a user, one or moreport ranges for assignment to objects that belong to categories of theplurality of categories described by the one or more dimensions of thetags; and distributing, by the centralized controller and to respectivepolicy agents of the one or more computing devices, a plurality ofpolicies, wherein each policy of the plurality of policies includes oneor more policy rules, wherein each policy rule of the one or more policyrules specifies one or more of the tags and a corresponding port rangeof the one or more port ranges, and wherein each policy of the pluralityof policies causes the respective policy agents to assign the one ormore port ranges to the objects that belong to the categories of theplurality of categories described by the one or more dimensions of theone or more of the tags.

In another example, this disclosure describes centralized controller fora computer network configured to: assign, to a plurality of categoriesthat support application workloads, tags specifying one or moredimensions of a plurality of dimensions for the application workloads,wherein the application workloads are executed by one or more computingdevices of the computer network, and wherein the one or more computingdevices include the plurality of categories; receive, from a user, oneor more port ranges for assignment to objects that belong to categoriesof the plurality of categories described by the one or more dimensionsof the tags; and distribute, to respective policy agents of the one ormore computing devices, a plurality of policies, wherein each policy ofthe plurality of policies includes one or more policy rules, whereineach policy rule of the one or more policy rules specifies one or moreof the tags and a corresponding port range of the one or more portranges, and wherein each policy of the plurality of policies causes therespective policy agents to assign the one or more port ranges to theobjects that belong to the categories of the plurality of categoriesdescribed by the one or more dimensions of the one or more of the tags.

The details of one or more examples of the techniques of this disclosureare set forth in the accompanying drawings and the description below.Other features, objects, and advantages of the techniques will beapparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an example network having a datacenter in which examples of the techniques described herein may beimplemented.

FIG. 2 is a block diagram illustrating an example implementation of thedata center of FIG. 1 in further detail.

FIG. 3 is a block diagram illustrating an example of a plurality of datacenters in which examples of the techniques described herein may beimplemented.

FIG. 4 is a block diagram illustrating a computing device that executesan example virtual router for virtual networks according to techniquesdescribed herein.

FIG. 5 is a block diagram illustrating an example message that includestag information in accordance with techniques described herein.

FIG. 6 is a flowchart illustrating an example operation in accordancewith the techniques of the disclosure.

Like reference characters refer to like elements throughout the figuresand description.

DETAILED DESCRIPTION

FIG. 1 is a block diagram illustrating an example network system inwhich examples of the techniques described herein may be implemented.Network system 2 in the example of FIG. 1 includes data centers 10A-10X(collectively, “data centers 10”) interconnected with one another andwith customer networks associated with customers 11 via a serviceprovider network 7. In general, each data center 10 provides anoperating environment for applications and services for customers 11coupled to the data center by service provider network 7. Data centers10 may, for example, host infrastructure equipment, such as networkingand storage systems, redundant power supplies, and environmentalcontrols. Service provider network 7 may be coupled to one or morenetworks administered by other providers, and may thus form part of alarge-scale public network infrastructure, e.g., the Internet.

In some examples, each data center 10 may represent one of manygeographically distributed network data centers. As illustrated in theexample of FIG. 1, each of data centers 10 may be a facility thatprovides network services for customers 11. Customers 11 may becollective categories such as enterprises and governments orindividuals. For example, a network data center may host web servicesfor several enterprises and end users. Other exemplary services mayinclude data storage, virtual private networks, traffic engineering,file service, data mining, scientific- or super-computing, and so on. Insome embodiments, each of data centers 10 may be individual networkservers, network peers, or otherwise.

In this example, each of data centers 10 includes a set of storagesystems and application servers 12A-12X (herein, “servers 12”)interconnected via high-speed switch fabric 14 provided by one or moretiers of physical network switches and routers. Switch fabric 14 isprovided by a set of interconnected top-of-rack (TOR) switches 16A-16BN(collectively, “TOR switches 16”) coupled to a distribution layer ofchassis switches 18A-18M (collectively, “chassis switches 18”). Althoughnot shown, each of data centers 10 may also include, for example, one ormore non-edge switches, routers, hubs, gateways, security devices suchas firewalls, intrusion detection, and/or intrusion prevention devices,servers, computer terminals, laptops, printers, databases, wirelessmobile devices such as cellular phones or personal digital assistants,wireless access points, bridges, cable modems, application accelerators,or other network devices.

In this example, TOR switches 16 and chassis switches 18 provide servers12 with redundant (multi-homed) connectivity to IP fabric 20 and serviceprovider network 7. Chassis switches 18 aggregate traffic flows andprovide high-speed connectivity between TOR switches 16. TOR switches 16may be network devices that provide layer two (e.g., MAC) and/or layer 3(e.g., IP) routing and/or switching functionality. TOR switches 16 andchassis switches 18 may each include one or more processors and amemory, and are capable of executing one or more software processes.Chassis switches 18 are coupled to IP fabric 20, which performs layer 3routing to route network traffic between data centers 10 and customers11 by service provider network 7.

Centralized controller 22 provides a logically and in some casesphysically centralized controller for facilitating operation of one ormore virtual networks across data centers 10, such as data center 10A,in accordance with one or more embodiments of this disclosure. In theexample of FIG. 1, each data center 10 includes a separate centralizedcontroller 22 that facilitates operations within the corresponding datacenter 10. In other examples, system 8 includes a single centralizedcontroller that facilitates operations across system 8. In someexamples, centralized controller is a virtual network controller (VNC).In some examples, centralized controller 22 may operate in response toconfiguration input received from network administrator 24. Additionalinformation regarding centralized controller 22 operating in conjunctionwith other devices of data center 10A or other software-defined networkis found in International Application Number PCT/US2013/044378, filedJun. 5, 2013, and entitled PHYSICAL PATH DETERMINATION FOR VIRTUALNETWORK PACKET FLOWS, which is incorporated by reference as if fully setforth herein.

Typically, the traffic between any two network devices, such as betweennetwork devices (not shown) within IP fabric 20 or between servers 12and customers 11 or between servers 12, for example, can traverse thephysical network using many different paths. A packet flow (or “flow”)can be defined by the five values used in a header of a packet, or“five-tuple,” i.e., the protocol, Source IP address, Destination IPaddress, Source port and Destination port that are used to route packetsthrough the physical network. For example, the protocol specifies thecommunications protocol, such as TCP or UDP, and Source port andDestination port refer to source and destination ports of theconnection. A set of one or more packet data units (PDUs) that match aparticular flow entry represent a flow. Flows may be broadly classifiedusing any parameter of a PDU, such as source and destination data link(e.g., MAC) and network (e.g., IP) addresses, a Virtual Local AreaNetwork (VLAN) tag, transport layer information, a Multiprotocol LabelSwitching (MPLS) or Generalized MPLS (GMPLS) label, and an ingress portof a network device receiving the flow. For example, a flow may be allPDUs transmitted in a Transmission Control Protocol (TCP) connection,all PDUs sourced by a particular MAC address or IP address, all PDUshaving the same VLAN tag, or all PDUs received at the same switch port.

In some examples, each of data centers 10 may have a need to implementdifferent policies within different computing environments according tothe needs of the particular environment. For example, a developmentenvironment, a staging environment, and a production environment of datacenter 10A may each use different port ranges for the same applications.Furthermore, multiple data centers 10 across different geographiclocations may implement different port ranges for the same applicationswithin each of their respective internal computing environments due todifferent customer requirements, networking resources andconfigurations, etc. If each computing environment within each of datacenters 10 were to independently manage its own port range assignments,an administrator may have difficulty ensuring that each policy meetssecurity, reliability, and quality requirements. For example, a firewallpolicy intended to set firewall permissions for a particular applicationusing a port range in a development environment would not function asintended if applied to a production environment that used a differentport range for the same application. Furthermore, if each computingenvironment within each data center were to independently manage its ownport range assignments, upgrading one or more of the policies across themultiple data centers may become cumbersome or unmanageable.

In accordance with the techniques of the disclosure, network system 8implements a scalable, multi-dimensional policy framework to supportflexible application of policies for controlling network traffic amongworkloads executing within one or more computing environments for datacenters 10 that may be categorized along multiple different dimensions.Such categories may include applications, deployments, applicationtiers, geographic sites, virtual networks, virtual machines, interfaces,projects, security requirements, quality requirements, physical devices,such as routers or switches, users, or compliance requirements, forexample. Each type of category represents a dimension for workloads thatgenerate or consume network traffic of data centers 10. In someexamples, the policy framework described herein permits centralizedcontroller 22 to tag objects that execute or otherwise enable workloadswith specific dimensions across multiple levels. Additional descriptionof the implementation of scalable, multi-dimensional policy frameworksto support flexible application of policies for controlling networktraffic among workloads executing within one or more computingenvironments may be found, for example, in U.S. application Ser. No.15/819,522, entitled “SCALABLE POLICY MANAGEMENT FOR VIRTUAL NETWORKS”and filed on Nov. 21, 2017, the entire content of which is incorporatedby reference. By using such a policy framework as described herein, anadministrator may create flexible and scalable policies for assigningport ranges across a plurality of different dimensions in the network.

In some examples, an administrator may define tags that specify one ormore dimensions that correspond to categories to which one or moreobjects of system 8 belong. Example categories of such objects include aglobal environment level, a project level, a virtual network level, avirtual machine level, and an interface level. In one example, tags mapsecurity requirements for the objects. Centralized controller 22receives the tags and assigns the tags to objects that belong tocategories that correspond to one or more dimensions of the tags. Forexample, centralized controller 22 may examine an object within system8, determine that the object belongs to a category that corresponds toone or more dimensions of the tags, and stores a mapping between theobject and the tag in a memory of centralized controller 22.

As described herein, a “tag” refers to a data structure that providesinformation to categorize an object according to a particular value orset of values. In some examples, the tag comprises a unique identifier.In some examples, an administrator defines a key/value pair for eachtag, wherein the key describes a category of the object, and the valueprovides a descriptor for the category. Centralized controller 22generates, for each tag, a unique identifier based on the key/valuepair. A policy agent for server 12A receives, from centralizedcontroller 22, the tag comprising the unique identifier during policyevaluation, as described below. In further examples, the policy agentfor server 12A receives, from centralized controller 22, the tagcomprising the unique identifier as part of a route exchange.

As an example, wherein the administrator provides a first key/value pairfor a tag, the key of the tag is an “application,” and the valueassociated with the key is a “finance” application. Example levels(e.g., example categories) of such objects include a global environmentlevel, a project level, a virtual network level, a virtual machinelevel, and an interface level. In one example, tags map securityrequirements for the objects. Tags may be predefined (e.g., such as atag for an application, deployment, application tier, or geographicsite), or may be implicitly assigned by centralized controller 22 duringprovisioning (e.g., such as a tag including an identifier correspondingto infrastructure, a rack, cluster, or data center which is provisionedto support the application). In some examples, multiple tags are appliedto a single object (e.g., an “application” and “geographic site” tag maybe applied to a single virtual machine), but the object may only have asingle tag per type and/or category. In further examples, anadministrator may define “labels” to be used as keys for the key/valuepairs of tags such that the user may customize or create his or her owncategories for tagging objects. Furthermore, as used herein, “tagging”an object refers to categorizing the object in a category specified by atag. In some examples, centralized controller 22 may “tag” an object bycategorizing the object in a category specified by a tag and storing thecategorization in a memory of controller 22. specify one or more tagsand one or more port ranges for assignment to objects that belong tocategories described by the one or more dimensions of the tags.

In further examples, an administrator may define one or more policiesthat include one or more policy rules that specify one or more tags andone or more port ranges for assignment to objects that belong tocategories described by the one or more dimensions of the tags.Centralized controller 22 receives the policies and distributes thepolicies to distributed policy agents executing on computing devicesthat host the workloads. The distributed policy agents may apply thepolicies to objects that belong to categories described by one or moredimensions of a tag of a given policy rule to assign one or more portranges of the given rule to the object. At least in some cases, thepolicy agents apply the policies at the interface level of one or morevirtual machines to correlate defined port ranges with specificapplications. Thus, such policies may be used to enable the use ofhigh-level, object-specific firewall policies that describe permissionsfor network traffic flowing to and/or from interfaces of the one or morevirtual machines.

In some examples, an extension of Border Gateway Protocol (BGP) isdescribed for communicating the policy framework between categories. Forexample, a policy agent may receive from a policy controller a BGPmessage that includes an extended community specifying one or morepolicy rules, each policy rule including one or more tags that includeone or more key/value pairs corresponding to categories that include theobjects. Further, each policy rule of the one or more policy rules mayassign a port range for use by the objects the belong to categoriesdescribed by the one or more tags. Additional information with respectto the implementation of BGP extended communities is described in “BGPExtended Communities Attribute,” RFC 4360, Internet Engineering TaskForce (IETF), February 2006, available athttps://tools.ietf.org/rfc/rfc4360, the entire contents of which isincorporated herein by reference. Thus, the techniques of the disclosuremay allow for scalable deployment of policies for assigning port rangesacross different environments within a plurality of data centers 10.Further, the techniques of the disclosure may reduce the complexity andsimplify management of such policies for assigning port ranges withinthe plurality of data centers 10.

FIG. 2 is a block diagram illustrating an example implementation of datacenter 10A of FIG. 1 in further detail. In the example of FIG. 2, datacenter 10A includes an overlay network that extends switch fabric 14from physical switches 16, 18 to software or “virtual” routers 30A-30X(collectively, “virtual routers 30”). Virtual routers 30 dynamicallycreate and manage one or more virtual networks 34 usable forcommunication between application instances. In one example, virtualrouters 30 execute the virtual network 34 as an overlay network, whichprovides the capability to decouple an application's virtual addressfrom a physical address (e.g., IP address) of the one of servers 12A-12X(“servers 12”) on which the application is executing. Each virtualnetwork 34 may use its own addressing and security scheme and may beviewed as orthogonal from the physical network and its addressingscheme. Various techniques may be used to transport packets within andacross virtual networks 34 over the physical network. In some examples,the techniques described in this disclosure provide multicast servicewithin virtual networks 34 without requiring multicast support in theunderlying physical network.

Each virtual router 30 may execute within a hypervisor, a host operatingsystem or other component of each of servers 12. Each of servers 12 mayrepresent an x86 or other general-purpose or special-purpose servercapable of executing virtual machines 36. In the example of FIG. 2,virtual router 30A executes within hypervisor 31, also often referred toas a virtual machine manager (VMM), which provides a virtualizationplatform that allows multiple operating systems to concurrently run onone of servers 12. In the example of FIG. 2, virtual router 30A managesvirtual networks 34, each of which provides a network environment forexecution of one or more virtual machines (VMs) 36 on top of thevirtualization platform provided by hypervisor 31. Each VM 36 isassociated with one of the virtual networks VN0-VN2 and may representtenant VMs running customer applications such as Web servers, databaseservers, enterprise applications, or hosting virtualized services usedto create service chains. In some cases, any one or more of servers 12or another computing device may host customer applications directly,i.e., not as virtual machines. In some cases, some of VMs 36 mayrepresent containers, another form of virtualized execution environment.That is, both virtual machines and containers are examples ofvirtualized execution environments for executing workloads.

In general, each VM 36 may be any type of software application and maybe assigned a virtual address for use within a corresponding virtualnetwork 34, where each of the virtual networks may be a differentvirtual subnet provided by virtual router 30A. A VM 36 may be assignedits own virtual layer three (L3) IP address, for example, for sendingand receiving communications but may be unaware of an IP address of thephysical server 12A on which the virtual machine is executing. In thisway, a “virtual address” is an address for an application that differsfrom the logical address for the underlying, physical computer system,e.g., server 12A in the example of FIG. 1 or 2.

In one implementation, each of servers 12 includes a corresponding oneof virtual network (VN) agents 35A-35X (collectively, “VN agents 35”)that controls the overlay of virtual networks 34 and that coordinatesthe routing of data packets within server 12. In general, each VN agent35 communicates with virtual network controller 22, which generatescommands to control routing of packets through data center 10A. VNagents 35 may operate as a proxy for control plane messages betweenvirtual machines 36 and virtual network controller 22. For example, a VM36 may request to send a message using its virtual address via the VNagent 35A, and VN agent 35A may in turn send the message and requestthat a response to the message be received for the virtual address ofthe VM 36 that originated the first message. In some cases, a VM 36 mayinvoke a procedure or function call presented by an applicationprogramming interface of VN agent 35A, and the VN agent 35A may handleencapsulation of the message as well, including addressing. Inaccordance with the techniques of the disclosure, each VN agent 35further includes a respective policy agent 139A-139X (collectively,policy agents 139″) for applying one or more policies to one or morecategories, as will described in more detail below.

In the example of FIG. 2, VN agents 35 are depicted as separate fromvirtual routers 30. However, in some examples, each VN agent 35 isexecuted by a corresponding hypervisor 31 and/or is a component of arespective virtual router 30. In some examples, one VN agent 35coordinates the routing of data packets for one corresponding server 12.In some examples, one VN agent 35 coordinates the routing of datapackets for one corresponding virtual router 30. In other examples, oneVN agent 35 coordinates the routing of data packets for a plurality ofservers 12 or for a plurality of virtual routers 30.

In one example, network packets, e.g., layer three (L3) IP packets orlayer two (L2) Ethernet packets generated or consumed by the instancesof applications executed by virtual machines 36 within the virtualnetwork domain may be encapsulated in another packet (e.g., another IPor Ethernet packet) that is transported by the physical network. Thepacket transported in a virtual network may be referred to herein as an“inner packet” while the physical network packet may be referred toherein as an “outer packet” or a “tunnel packet.” Encapsulation and/orde-capsulation of virtual network packets within physical networkpackets may be performed within virtual routers 30, e.g., within thehypervisor or the host operating system running on each of servers 12.As another example, encapsulation and de-capsulation functions may beperformed at the edge of switch fabric 14 at a first-hop TOR switch 16that is one hop removed from the application instance that originatedthe packet. This functionality is referred to herein as tunneling andmay be used within data center 10A to create one or more overlaynetworks. Besides IPinIP, other example tunneling protocols that may beused include IP over GRE, VxLAN, MPLS over GRE, MPLS over UDP, etc.

As noted above, centralized controller 22 provides a logicallycentralized controller for facilitating operation of one or more virtualnetworks within data center 10A. Centralized controller 22 may, forexample, maintain a routing information base, e.g., one or more routingtables that store routing information for the physical network as wellas one or more overlay networks of data center 10A. Similarly, switches16, 18 and virtual routers 30 maintain routing information, such as oneor more routing and/or forwarding tables. In one example implementation,virtual router 30A of hypervisor 31 implements a network forwardingtable (NFT) 32 for each virtual network 34. In general, each NFT 32stores forwarding information for the corresponding virtual network 34and identifies where data packets are to be forwarded and whether thepackets are to be encapsulated in a tunneling protocol, such as with atunnel header that may include one or more headers for different layersof the virtual network protocol stack.

In accordance with the techniques of the disclosure, centralizedcontroller 22 further includes policy controller 23. Policy controller23 is configured to receive, from an administrator, a plurality of tagsacross a plurality of dimensions. Policy controller 23 is furtherconfigured to tag a plurality of objects across a plurality of levelswith the tags and store the categorizations for the objects in a memoryof policy controller 23. In some examples, the plurality of levelsinclude a level of an object, such as a global environment level, aproject level, a virtual network level, a virtual machine level, or aninterface level of the object. In further examples, policy controller 23tags the plurality of objects across a plurality of categories. In someexamples, the plurality of categories include applications executingwithin VMs 36, deployments, application tiers, geographic sites, virtualnetworks, VMs 36, interfaces, projects, security requirements, qualityrequirements, users, or compliance requirements.

Furthermore, policy controller 23 receives a plurality of policies thatspecify one or more tags and one or more port ranges for assignment toobjects that belong to categories described by the one or moredimensions of the tags. In some examples, policy controller 23 receivesthe plurality of policies from a user or administrator of network system8. Policy controller 23 distributes, to respective policy agents 139 ofVN agents 35, the plurality of policies.

Upon receiving the plurality of policies, each policy agent 139 appliesthe one or more policy rules of each of the plurality of policies toobjects corresponding to tags of the one or more policy rules to controlnetwork traffic between the objects. For example, policy agents 139,under the direction of policy controller 23, express the one or morepolicy rules at logical interfaces of VMs 36 that are tagged with tagscorresponding to tags of the one or more policy rules so as to assignport ranges specified by the one or more policy rules to the logicalinterfaces of VMs 36 that are tagged with tags corresponding to tags ofthe one or more policy rules. Policy agents 139 may use the port rangesdefined by the policy rules of the policies to identify network trafficreceived on ports of the logical interfaces as belonging to specificobjects. Policy agents 139 may apply object-specific firewall rules tothe network traffic to block or permit the network traffic based on anidentified object associated with the network traffic.

For example, an administrator may specify one or more port ranges foruse by an object that belongs to a particular category described the oneor more dimensions of the tags. Thus, as described in further detailbelow, policy agents 139 may use a port of a network traffic flow toidentify an object associated with the network traffic flow according tothe assigned port ranges specified by the one or more policy rulesincluded in the policy of the plurality of policies. Policy agents 139may apply, based on the identified object, object-specific firewallpolicies to the network traffic flow to allow or block the networktraffic flow in accordance with the object-specific firewall policies.Accordingly, the techniques of the disclosure may allow for theimplantation of object-specific or application-specific firewallpolicies across a number of different dimensions of network system 2.

As an illustration of the above, in the example of FIG. 2, policy agent139A under the direction of policy controller 23 has tagged virtualmachines VM0 36, VM1 36, VM2 36, and VM3 36 as belonging to a categorydescribed by tag 1. Further, policy agent 139A has categorized virtualnetworks VN0 34, VN1 34, and VN2 34 in a category described by tag 2,respectively. Furthermore, virtual machines VM0 36, VM1 36, and VM2 36belong to a first project 33, which policy agent 139A has categorized asbelonging to a category described by tag 3. Still further, policy agent139A has categorized server 1 12A as belonging to a category describedby tag 4.

In some examples, the one or more policy rules describe one or more portranges and one or more tags, each of the tags specifying one or morecategories for application of the policy rules. Based on the one or moreport ranges and the one or more tags, each policy agent 139 may identifynetwork traffic as belonging to objects that belong to categoriesdescribed by the one or more tags. In other examples, each of the one ormore policy rules describe one or more port ranges for one or moreapplications, networks, or global objects. Thus, by applying the policyrules as described herein, policy agents 139 may apply specific policyrules so as to enable workloads with specific dimensions. Accordingly,the techniques of the disclosure may allow for scalable deployment ofpolicies for port range assignment across different environments withina plurality of data centers 10. Further, the techniques of thedisclosure may reduce the complexity and simplify management of suchpolicies for port range assignment within the plurality of data centers10.

In some examples, policies are “inherited” in that policies applied toparent objects are likewise applied to objects that are children of theparent objects in a hierarchical fashion. As one example, policy agent139A receives a first policy rule that includes tag 3 that is applied toproject 33. Policy agent 139A applies the first policy rule to project33. Policy agent 139A further applies the first policy rule to childrenof the first project, such as virtual networks, virtual machines, andinterfaces within the first project, but not to virtual networks,virtual machines, and interfaces within a second project, so as toassign a port range to the first project and objects within the firstproject as specified by the first policy rule. In the example of FIG. 2,policy agent 139A applies the first policy rule to virtual machines VM036, VM1 36, and VM2 36 because virtual machines VM0 36, VM1 36, and VM236 are children of project 33. However, policy agent 139A does not applythe first policy rule to virtual machine VM3 36, which is not part ofproject 33.

Continuing the forgoing example, policy agent 139A receives a secondpolicy rule that includes tag 1 that describes virtual machines 36.Policy agent 139A therefore applies both the first policy rule and thesecond policy rule to virtual machines VM0 36, VM1 36, and VM2 36.Further, policy agent 139A applies both the first policy rule and thesecond policy rule to interfaces of virtual machines VM0 36, VM1 36, andVM2 36 (not depicted), which are children objects of virtual machines36. However, policy agent 139A does not apply the second policy rule toproject 33 because project 33 is a parent, not a child, of virtualmachines VM0 36, VM1 36, and VM2 36.

In some examples of the techniques of the disclosure, the policyframework implements complex regular expressions to apply tags for suchpolicies to specific environments or infrastructure. For example, eachtag specified by each policy rule may further include a uniqueidentifier. Policy agent 139 may apply regular expressions to groupand/or segment workloads based on the unique identifier. As a furtherexample, policy agent 139A applies a match condition to match the uniqueidentifier of each tag with objects that belong to categoriescorresponding to the unique identifier. Thus, global policies may bedistributed to a plurality of policy agents 139, and each policy agent139 may selectively apply only those policy rules that include tags thatspecify unique identifiers that correspond to objects that belong tocategories corresponding to the unique identifiers.

In some examples, policy controller 23 distributes one or more tags viaa Border Gateway Protocol (BGP) route. For example, such a BGP messagemay specify one or more tags for an object as an extended community forBGP. Additional information with respect to BGP is described in “BGPMPLS-Based Ethernet VPN,” RFC 7432, Internet Engineering Task Force(IETF), February 2015, available at https://tools.ietf.org/html/rfc7432,the entire contents of which is incorporated herein by reference.

FIG. 3 is a block diagram illustrating an example of a plurality of datacenters 10 in which examples of the techniques described herein may beimplemented. Each of data centers 10A-10X (collectively “datacenters10”) may operate in a substantially similar fashion to datacenters 10 ofFIG. 1 and FIG. 2. In some examples, one or more of datacenters 10implements a cloud environment executing Openstack, while in anotherexample, one or more of data centers 10 is a cloud environment executingKubernetes, while in yet another example, one or more of data centers 10implements a cloud environment executing Amazon Web Services, while inyet another example, one or more of data centers 10 executes on “baremetal” infrastructure. In some examples, each of data centers 10executes a different infrastructure than each other data center 10.

In the example of FIG. 3, Each data centers 10 comprises a database 308and three different environments: a development environment 310, astaging environment 312, and a production environment 314. Eachenvironment of each data center 10 is capable of executing one or moreapplications 302A-302D (collectively, “applications 302”), such asapplication 302A executing within development environment 310A of datacenter 10A, application 302B executing within production environment314A of data center 10A, application 302C executing within developmentenvironment 310B of data center 10B, and application 302D executingwithin staging environment 312B of data center 10B. In one example, eachapplication 302 is an instance of the same type of finance application.Policies as described herein are robust and extensible for applicationin many different types of cloud environments described above.

Within an environment, each application may include a plurality ofprocesses and sub-processes. In the example of FIG. 3, application 302Aof development environment 310A executes web process 304A andApplication Program Interface (API) process 306A. Further, application302B of production environment 314A executes web process 304B and APIprocess 306B. Application 302C of development environment 310B executesweb process 304C and API process 306C. Still further, application 302Dof staging environment 312B executes web process 304D and API process306D. However, in other examples, each application 302 of a respectiveenvironment 310A, 312A, 314A, 310B, 312B, or 314B may execute additionalor different processes than each other application 302. Furthermore, insome examples, the applications executed within each respectiveenvironment 310A, 310B, 312A, 312B, 314A, and 314B may be similar ordifferent from the applications executed within each other environment310A, 310B, 312A, 312B, 314A, and 314B.

It may be desirable to ensure that processes 304, 306 of eachapplication 302 of a respective environment 310, 312, 314 does notexchange network traffic with processes 304, 306 of an application 302within a different environment 310, 312, 314, while still permittingnetwork traffic to flow between different processes 304, 306 within thesame application 302. For example, an administrator may desire to allownetwork traffic between web process 304A and API process 306A becauseeach of web process 304A and API process 306A operate within the sameapplication 302A within development environment 310A. Further, theadministrator may desire to prevent network traffic between web process304A (e.g., operating within development environment 310A of data center10A) and API process 306B (e.g., operating within production environment314A of data center 10A) or between web process 304A (e.g., operatingwithin development environment 310A of data center 10A) and API process306C (e.g., operating within development environment 310B of data center10B). Further, an administrator may desire to permit processes 304, 306executing within an application 302 within the same data center 10 toaccess the same database 308, regardless of the specific environment310, 312, or 314 within which the particular application 302 executes.For example, an administrator may desire to allow API process 306Aexecuting within application 302A and API process 306B executing withinapplication 302B to each access database 308A.

The administrator may also desire to allocate different port ranges foruse by each of application 302A, application 302B, application 302C,and/or application 302D to satisfy various security requirements,quality requirements, compliance requirements, or user requirements.Thus, if the administrator were to implement a singleapplication-specific firewall policy (e.g., a firewall policy specificto the application type of each of applications 302A, 302B, 302C, and302D), the firewall policy may not function as intended because each ofapplications 302A, 302B, 302C, and 302D use different port ranges.Furthermore, if the administrator were to independently manage networktraffic policies for each process 304, 306 within each application 302within each environment 312, 312, and 314 within each data center 10,the administrator may have difficulty ensuring that each network trafficpolicy meets security, reliability, and quality requirements.Furthermore, upgrading one or more of the policies across multiple datacenters 10 may become cumbersome or unmanageable.

In accordance with the techniques of the disclosure, one or more tagsspecifying one or more categories are applied to each process 304, 306.As depicted in the example of FIG. 3, policy controller 23 ofcentralized controller 22 applies tag “1A” to web process 304A, whichspecifies that web process 304A belongs to development environment 310A.Similarly, policy controller 23 applies tag “2A” to API process 306A,which specifies that web process 304A belongs to development environment310A. In contrast, policy controller 23 applies tag “1B” to web process304B and tag “2B” to API process 306B, each of which specify that therespective application belongs to production environment 314A.Furthermore, tag “1C” is applied to web process 304C and tag “2C” isapplied API process 306C, each of which specify that the respectiveapplication belongs to development environment 310B; and tag “1D” isapplied to web process 304D and tag “2D” is applied to API process 306D,each of which specify that the respective application belongs to stagingenvironment 312B.

In one example, a policy agent 139 of a VN agent 35 receives, frompolicy controller 23, one or more policies specifying one or more policyrules for assigning port ranges to one applications 302 that belong tocategories described by one or more tags of the one or more policyrules. For example, each of the one or more policy rules specify one ormore port ranges and one or more tags, each of the tags specifying oneor more categories for application of the policy rules. Policy agent 139applies, to each process 304, 306 of each application 302, only thosepolicy rules that include tags matching tags applied to respectiveprocesses 304, 306.

For example, policy agent 139 may receive a first policy rule thatassigns a first port range for web processes 304 and includes tag 1B.Policy agent 139 may examine each of web processes 304A, 304B, 304C, and304D but apply the policy rule only to web process 304B because webprocess 304B is categorized within the same category as specified by tag1B. VN agent 35 may subsequently receive traffic originating from ordestined to a first port within the first port range and identify webprocess 304B as associated with the traffic. VN agent 35 maysubsequently apply an application-specific firewall policy (e.g., afirewall policy specific to web process 304B) to the traffic originatingfrom or destined to the first port. For example, VN agent 35 may allownetwork traffic flowing from an interface of a virtual machine executingweb process 304B to an interface of a virtual machine executing APIprocess 306B and block other traffic flowing to the interface of thevirtual machine executing API process 306B, such as traffic flowing froman interface of a virtual machine executing web process 304A.

Similarly, policy agent 139 may receive a second policy rule thatassigns a second port range to API processes 306 and includes tags 2Aand 2B. Policy agent 139 may examine each of API processes 306A, 306B,306C, and 306D, but apply the policy rule only to API processes 306A and306B because API processes 306A and 306B are categorized within the samecategory as specified by tags 2A and 2B, respectively. VN agent 35 maysubsequently receive traffic originating from or destined to a secondport within the second port range and identify at least one of APIprocesses 306A and/or 306B as associated with the traffic. VN agent 35may subsequently apply an application-specific firewall policy (e.g., afirewall policy specific to API processes 306A and 306B) to the trafficoriginating from or destined to the second port. For example, VN agent35 may permit network traffic flowing from either an interface of avirtual machine executing API process 306A or the interface of thevirtual machine executing API process 306B to an interface of database308A and block other traffic flowing to other destinations, such astraffic flowing from an interface of a virtual machine executing APIprocess 306B to an interface of database 308B.

As depicted in the foregoing example, the second policy rule may specifytags 2A and 2B in a Boolean expression, e.g., (2A OR 2B). However, inaccordance with the techniques of the disclosure, each policy rule mayfurther include complex regular expressions that specify tags for one ormore objects. For example, a policy rule may include one or more Booleanoperators (e.g., AND, OR, NOT), mathematical operators (e.g., addition,subtraction, multiplication, division), bit-shifting operations, matrixoperations, text parsing operators, or a combination of any of theforegoing.

In the foregoing examples, policy agent 139 may apply whitelisting, inthat all traffic between assigned port ranges of interfaces of virtualmachines is preemptively blocked, and policy agent 139 may apply, basedon the specified port ranges, one or more application-specific firewallpolicy rules that whitelist traffic flows having specific port ranges(e.g., specify traffic flows having specific port ranges of interfacesof virtual machines that correspond to applications that are permitted).In other examples, policy agent 139 may apply blacklisting, in that alltraffic between assigned port ranges of interfaces of virtual machinesis preemptively allowed, and policy agent 139 may apply, based on thespecified port ranges, one or more application-specific firewall policyrules that blacklist traffic flows having specific port ranges (e.g.,specify traffic flows having specific port ranges of interfaces ofvirtual machines that correspond to applications that are blocked). Inalternate examples, policy agent 139 may apply, based on the specifiedport ranges, one or more application-specific firewall policy rules thatinclude a combination of whitelisting or blacklisting specific trafficflows or groups of traffic flows having specific port ranges ofinterfaces of virtual machines that correspond to specific applicationsthat are allowed or blocked.

In the example of FIG. 3, policy controller 23 maintains global policies300 specifying tags describing the specific environments to whichprocesses 304, 306 belong. However, in other examples, policy controller23 maintains tags that describe other categories for organizingprocesses 304, 306. For example, tags for processes 304, 306 mayadditionally, or alternatively, specify one or more application types,deployments, application tiers, geographic sites, virtual networks,virtual machines, interfaces, projects, security requirements, qualityrequirements, users, or compliance requirements.

For examples, one or more of data centers 10 implements a cloudenvironment executing OpenStack. In this example, the cloud environmentsupports three projects, each providing a finance application comprisingthree virtual networks. Within such a data center 10, policy controller23 may assign one or more tags at a project level. For example, policycontroller 23 may assign a tag comprising a key of “application” and avalue of “finance” and a tag comprising a key of “deployment” and avalue of “development” to a first project. Policy controller 23 mayassign a tag comprising a key of “application” and a value of “finance”and a tag comprising a key of “deployment” and a value of “staging” to asecond project. Policy controller 23 may assign a tag comprising a keyof “application” and a value of “finance” and a tag comprising a key of“deployment” and a value of “production” to a third project. Further,within each project, policy controller 23 may assign tags to each of thethree virtual networks. For example, policy controller 23 assigns a tagcomprising a key of “tier” and a value of “web” to a first virtualnetwork, a tag comprising a key of “tier” and a value of “application”to a second virtual network, and a tag comprising a key of “tier” and avalue of “database” to a third virtual network. Policy controller 23distributes one or more policies, each policy including one or morepolicy rules to policy agent 139, which applies the one or more policyrules of the policies to interfaces of virtual machines within the datacenter 10 based on the tags applied to the projects and virtualnetworks.

In some examples, one or more of data centers 10 is a cloud environmentexecuting Kubernetes. In this example, the cloud environment supportstwo namespaces, each providing a finance application comprising threevirtual networks. Within such a data center 10, policy controller 23 mayassign one or more tags at a namespace level. For example, policycontroller 23 may assign a tag comprising a key of “application” and avalue of “finance,” a tag comprising a key of “deployment” and a valueof “development,” and a tag comprising a key of “site” and a value of“US” to a first namespace. Policy controller 23 may assign a tagcomprising a key of “application” and a value of “finance,” a tagcomprising a key of “deployment” and a value of “production,” and a tagcomprising a key of “site” and a value of “US” to a second namespace.Further, within each namespace, policy controller 23 may assign tags toeach of the three virtual networks. For example, policy controller 23assigns a tag comprising a key of “tier” and a value of “web” to a firstvirtual network, a tag comprising a key of “tier” and a value of“application” to a second virtual network, and a tag comprising a key of“tier” and a value of “database” to a third virtual network. Policycontroller 23 distributes one or more policies including one or morepolicy rules to policy agent 139, which applies the one or more policyrules of the policies to interfaces of virtual machines within the datacenter 10 based on the tags applied to the projects and virtualnetworks.

In some examples, a first data center 10A implements a cloud environmentexecuting Amazon Web Services and a second data center 10B executes on“bare metal” infrastructure.” In this example, data center 10A supportsa first finance application comprising three virtual networks andexecuting within a development deployment, while data center 10Asupports a second finance application comprising three virtual networksand executing within a production deployment. In this example, policycontroller 23 may assign one or more tags at an application level. Forexample, policy controller 23 may assign a tag comprising a key of“application” and a value of “finance,” a tag comprising a key of“deployment” and a value of “development,” and a tag comprising a key of“site” and a value of “US” to the first application executing withindata center 10A. Policy controller 23 may further assign a tagcomprising a key of “application” and a value of “finance,” a tagcomprising a key of “deployment” and a value of “production,” and a tagcomprising a key of “site” and a value of “US” to the second applicationexecuting within data center 10B. Further, within each application,policy controller 23 may assign tags to each of the three virtualnetworks. For example, policy controller 23 assigns a tag comprising akey of “tier” and a value of “web” to a first virtual network, a tagcomprising a key of “tier” and a value of “application” to a secondvirtual network, and a tag comprising a key of “tier” and a value of“database” to a third virtual network. Policy controller 23 distributesone or more policies including one or more policy rules to policy agent139, which applies the one or more policy rules of the one or morepolicies to interfaces of virtual machines within the data center 10based on the tags applied to the projects and virtual networks.

In the example of FIG. 3, policy controller 23 is described asdistributing one or more policies including one or more policy rules,each policy rule including port ranges and tags for objects at a projectlevel. However, policy controller 23 may additionally or alternativelydistribute policies including policy rules that include tags specifyingvarious different object levels, such as a global environment level, aproject level, a virtual network level, a virtual machine level, or aninterface level.

In an example implementation of the techniques of the disclosure, policycontroller 23 uses a plurality of configuration objects to implement theone or more policies. As one example, policy controller 23 applies afirst set of configuration objects at a global level. The first setconfiguration objects includes global policies that specify globalpolicy rules that include global port ranges and global tags across aplurality of levels and/or categories. Policy controller 23 distributes,to policy agents 139, the first set of configuration objects at theglobal level. Policy agents 139 match global tags associated with globalpolicy rules and global port ranges to objects tagged with the globaltags. Based on the global policy rules, policy agents 139 assign globalport ranges to objects tagged with the global tags. Policy agents 139store an association between the tag and the one or more objects thatbelong to the categories of the plurality of categories described by theone or more dimensions of the tag. In other examples, policy agents 139may store, for each of the one or more objects that belong to thecategories of the plurality of categories described by the one or moredimensions of the tag, a corresponding assigned port range specified bythe tag.

Policy agents 139 may further receive network traffic originating fromor destined to ports within the global port ranges and identify, basedon a correspondence of source ports and/or destination ports of thenetwork traffic to the assigned global port ranges, global objects thatare associated with the network traffic. In response to identifying theglobal objects associated with the network traffic, policy agents 139may apply global firewall policies to the network traffic so as topermit or deny the network traffic.

Furthermore, policy controller 23 applies a second set of configurationobjects at a project level. The second set of configuration objectsincludes project-specific policies that include project-specific portranges and project-specific tags across a plurality of levels and/orcategories. Policy controller 23 distributes, to policy agents 139, thesecond set of configuration objects at the project level. Policy agents139 match project-specific tags associated with project-specific policyrules and project-specific port ranges to objects tagged with theproject-specific tags. Based on the project-specific policy rules,policy agents 139 assign project-specific port ranges to objects taggedwith the project-specific tags. Policy agents 139 may further receivenetwork traffic originating from or destined to ports within theproject-specific port ranges and identify, based on a correspondence ofthe source ports and/or destination ports of the network traffic to theassigned project-specific port ranges, project objects that areassociated with the network traffic. In response to identifying theproject objects associated with the network traffic, policy agents 139may apply project-specific firewall policies to the network traffic soas to permit or deny the network traffic.

In further examples, policy controller 23 may specify lower-levelconfiguration objects, such as application policies that specifyapplication policy rules that include application port ranges andapplication tags defined at a virtual network-specific level, a virtualmachine-specific level, and/or an interface-specific level. By doing so,policy controller 23 may apply a hierarchical set of policies to aplurality of objects tagged with corresponding hierarchical tags withinone or more data centers 10 to assign port ranges at anapplication-specific, virtual network-specific level, a virtualmachine-specific level, and/or an interface-specific level. Further,policy agents 139 may receive network traffic originating from ordestined to ports within the specified port ranges and identify, basedon a correspondence of the source ports and/or destination ports of thenetwork traffic to a particular level, lower-level objects that areassociated with the network traffic. For example, in response toidentifying an application associated with the network traffic based onthe network traffic having at least one of a source port or adestination port corresponding to a port range assigned for thatapplication, policy agent 139 may apply application-specific firewallpolicies to the network traffic so as to permit or deny the networktraffic. Thus, the techniques of the disclosure allow for distributionof simplified traffic policies that are scalable and robust across manydifferent types of deployments and execution environments.

FIG. 4 is a block diagram illustrating an example computing device 100that executes a virtual router 120 for virtual networks according totechniques described herein. Computing device 100 may represent any ofservers 12 of FIGS. 1-3 or other device, such as any of TOR switches 16.

Computing device 100 includes in this example a system bus 142 couplinghardware components of a computing device 100 hardware environment.System bus 142 couples memory 144, network interface cards (NICs)106A-106B (collectively, “NICs 106”), storage disk 107, and multi-corecomputing environment 102 having a plurality of processing cores108A-108J (collectively, “processing cores 108”). Network interfacecards 106 include interfaces configured to exchange packets using linksof an underlying physical network. Multi-core computing environment 102may include any number of processors and any number of hardware coresfrom, for example, four to thousands. Each of processing cores 108 eachincludes an independent execution unit to perform instructions thatconform to an instruction set architecture for the core. Processingcores 108 may each be implemented as separate integrated circuits (ICs)or may be combined within one or more multi-core processors (or“many-core” processors) that are each implemented using a single IC(i.e., a chip multiprocessor).

Disk 107 represents computer readable storage media that includesvolatile and/or non-volatile, removable and/or non-removable mediaimplemented in any method or technology for storage of information suchas processor-readable instructions, data structures, program modules, orother data. Computer readable storage media includes, but is not limitedto, random access memory (RAM), read-only memory (ROM), EEPROM, flashmemory, CD-ROM, digital versatile discs (DVD) or other optical storage,magnetic cassettes, magnetic tape, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to storethe desired information and that can be accessed by cores 108.

Main memory 144 includes one or more computer-readable storage media,which may include random-access memory (RAM) such as various forms ofdynamic RAM (DRAM), e.g., DDR2/DDR3 SDRAM, or static RAM (SRAM), flashmemory, or any other form of fixed or removable storage medium that canbe used to carry or store desired program code and program data in theform of instructions or data structures and that can be accessed by acomputer. Main memory 144 provides a physical address space composed ofaddressable memory locations.

Memory 144 may in some examples present a non-uniform memory access(NUMA) architecture to multi-core computing environment 102. That is,cores 108 may not have equal memory access time to the various storagemedia that constitute memory 144. Cores 108 may be configured in someinstances to use the portions of memory 144 that offer the lowest memorylatency for the cores to reduce overall memory latency.

In some instances, a physical address space for a computer-readablestorage medium may be shared among one or more cores 108 (i.e., a sharedmemory). For example, cores 108A, 108B may be connected via a memory bus(not shown) to one or more DRAM packages, modules, and/or chips (alsonot shown) that present a physical address space accessible by cores108A, 108B. While this physical address space may offer the lowestmemory access time to cores 108A, 108B of any of portions of memory 144,at least some of the remaining portions of memory 144 may be directlyaccessible to cores 108A, 108B. One or more of cores 108 may alsoinclude an L1/L2/L3 cache or a combination thereof. The respectivecaches for cores 108 offer the lowest-latency memory access of any ofstorage media for the cores 108.

Memory 144, network interface cards (NICs) 106A-106B (collectively,“NICs 106”), storage disk 107, and multi-core computing environment 102provide an operating environment for a software stack that executes avirtual router 120 and one or more virtual machines 110A-110K(collectively, “virtual machines 110”). Virtual machines 110 mayrepresent example instances of any of virtual machines 36 of FIG. 2. Thecomputing device 100 partitions the virtual and/or physical addressspace provided by main memory 144 and in the case of virtual memory bydisk 107 into user space 111, allocated for running user processes, andkernel space 112, which is protected and generally inaccessible by userprocesses. An operating system kernel (not shown in FIG. 4) may executein kernel space and may include, for example, a Linux, Berkeley SoftwareDistribution (BSD), another Unix-variant kernel, or a Windows serveroperating system kernel, available from Microsoft Corp. Computing device100 may in some instances execute a hypervisor to manage virtualmachines 110 (also not shown in FIG. 4). An example hypervisor 31 isillustrated in FIG. 2. Example hypervisors include Kernel-based VirtualMachine (KVM) for the Linux kernel, Xen, ESXi available from VMware,Windows Hyper-V available from Microsoft, and other open-source andproprietary hypervisors. In some examples, specialized hardwareprogrammed with routing information such as FIBs 124 may execute thevirtual router 120.

Eth0 114A and Eth1 114B represent devices according to a software devicemodel and provide device driver software routines for handling packetsfor receipt/transmission by corresponding NICs 106. Packets received byNICs 106 from the underlying physical network fabric for the virtualnetworks may include an outer header to allow the physical networkfabric to tunnel the payload or “inner packet” to a physical networkaddress for one of NICs 106. The outer header may include not only thephysical network address but also a virtual network identifier such as aVxLAN tag or Multiprotocol Label Switching (MPLS) label that identifiesone of the virtual networks as well as the corresponding routinginstance 122. An inner packet includes an inner header having adestination network address that conform to the virtual networkaddressing space for the virtual network identified by the virtualnetwork identifier. For example, virtual router forwarding plane 128 mayreceive by Eth1 from NIC 106 a packet having an outer header thanincludes a VxLAN associated in virtual router forwarding plane 128 withrouting instance 122A. The packet may have an inner header having adestination network address that is a destination address of VM 110Athat taps, via tap interface 146A, into routing instance 122A.

Virtual router 120 in this example includes a kernel space 112 module:virtual router forwarding plane 128, as well as a user space 111 module:VN agent 35. Virtual router forwarding plane 128 executes the“forwarding plane” or packet forwarding functionality of the virtualrouter 120 and VN agent 35 executes the “control plane” functionality ofthe virtual router 120. VN agent 35 may represent an example instance ofany of VN agents 35 of FIG. 2.

In the example of FIG. 4, VN agent 35 is depicted as a component ofvirtual router 120. However, in some examples, VN agent 35 is a separatecomponent from virtual router 120. In some examples, one VN agent 35coordinates the routing of data packets for one corresponding virtualrouter 120. In other examples, one VN agent 35 coordinates the routingof data packets for a plurality of virtual routers 120.

Virtual router forwarding plane 128 includes multiple routing instances122A-122C (collectively, “routing instances 122”) for correspondingvirtual networks. Each of routing instances 122 includes a correspondingone of forwarding information bases (FIBs) 124A-124C (collectively,“FIBs 124”) and flow tables 126A-126C (collectively, “flow tables 126”).Although illustrated as separate data structures, flow tables 126 may insome instances be logical tables implemented as a single table or otherassociative data structure in which entries for respective flow tables126 are identifiable by the virtual network identifier (e.g., a VRFidentifier such as VxLAN tag or MPLS label)). FIBS 124 include lookuptables that map destination addresses to destination next hops. Thedestination addresses may include layer 3 network prefixes or layer 2MAC addresses. Flow tables 126 enable application of forwarding policiesto flows. Each of flow tables 126 includes flow table entries that eachmatch one or more flows that may traverse virtual router forwardingplane 128 and include a forwarding policy for application to matchingflows. For example, virtual router forwarding plane 128 attempts tomatch packets processed by routing instance 122A to one of the flowtable entries of flow table 126A. If a matching flow table entry existsfor a given packet, virtual router forwarding plane 128 applies the flowactions specified in a policy to the packet. This may be referred to as“fast-path” packet processing. If a matching flow table entry does notexist for the packet, the packet may represent an initial packet for anew packet flow and virtual router forwarding plane 128 may request VNagent 35 to install a flow table entry in the flow table for the newpacket flow. This may be referred to as “slow-path” packet processingfor initial packets of packet flows and is represented in FIG. 4 by slowpath 140.

In this example, VN agent 35 may be a user space 111 process executed bycomputing device 100. VN agent 35 includes configuration data 134,virtual routing and forwarding instances configurations 136 (“VRFs136”), and policy table 138 (“policies 138”). VN agent 35 exchangescontrol information with one or more virtual network controllers (e.g.,centralized controller 22 of FIGS. 1-2). Control information mayinclude, virtual network routes, low-level configuration state such asrouting instances and forwarding policy for installation toconfiguration data 134, VRFs 136, and policies 138. VN agent 35 may alsoreport analytics state, install forwarding state to FIBS 124 of virtualrouter forwarding plane 128, discover VMs 110 and attributes thereof. Asnoted above, VN agent 35 further applies slow-path packet processing forthe first (initial) packet of each new flow traversing virtual routerforwarding plane 128 and installs corresponding flow entries to flowtables 126 for the new flows for fast path processing by virtual routerforwarding plane 128 for subsequent packets of the flows.

In accordance with the techniques of the disclosure, VN agent 35 furtherincludes tag rule database 141. Tag rule database 141 includes mappingsbetween tags and one or more objects that belong to one or morecategories described by one or more dimensions of the tags. As describedabove, policy controller 23 of centralized controller 22 assigns one ormore tags specifying one or more levels and/or one or more categoriesfor the objects. Policy controller 23 may apply tags to objects across aplurality of levels or categories, as well as apply the tags to objectsacross a plurality of data centers. Policy controller 23 distributespolicies including policy rules that comprise one or more tags and oneor more port ranges to VN agent 35, which stores the policies inpolicies 138.

VN agent 35 further includes a policy agent 139. Policy agent 139receives, from policy controller 23, one or more port range policies andstores such policies in policies 138. Each of policies 138 may includeone or more policy rules that specify at least one port range. Further,each policy rule includes one or more tags that specify to whichobjects, such as applications executing on VMs 110, the policy rulesapply. For example, VN agent 35 may receive a network flow comprising asource port and a destination port. Policy agent 139 may cross referencethe one or more tags of a policy rule with attributes of one or moreobjects stored in tag rule database 141 to identify one or more objectsassociated with the traffic flow. Policy agent 139 may retrieve afirewall policy corresponding to the identified object and apply thefirewall policy to the network flow to permit or block the network flow.

As one example, policy agent 139 receives, from policy controller 23, afirst policy rule that specifies a port range for interfaces 146 andincludes tag 1. Policy agent 139 may examine categories applied tointerfaces 146A, 146B, 146C, and 146D, determine that a category ofinterface 146A matches tag 1 of the first policy rule, and assign thespecified port range only to interface 146A. VN agent 35 (or another VNagent external to computing device 100), may subsequently identifyinterface 146A as associated with a first network traffic flowcomprising at least one of a source port or address port within thespecified port range. Based on the identification of interface 146A asassociated with the first network traffic flow, VN agent 35 (or anotherVN agent external to computing device 100), may identify global,project-specific, application-specific, or interface-specific firewallpolicy rules that include tags with which interface 146A is tagged andapply such firewall policy rules to allow or block the first networktraffic flow.

As another example, policy agent 139 receives, from policy controller23, a second policy rule specifies a port range for interfaces 146 andincludes tag 2. Policy agent 139 may examine categories applied tointerfaces 146A, 146B, 146C, and 146D, determine that a category ofinterface 146B matches tag 2 of the second policy rule, and assign thespecified port range only to interface 146B. VN agent 35 (or another VNagent external to computing device 100), may subsequently identifyinterface 146B as associated with a second network traffic flowcomprising at least one of a source port or address port within thespecified port range. Based on the identification of interface 146B asassociated with the second network traffic flow, VN agent 35 (or anotherVN agent external to computing device 100), may identify global,project-specific, application-specific, or interface-specific firewallpolicy rules that include tags with which interface 146B is tagged andapply such firewall policy rules to allow or block the second networktraffic flow.

To update policies for a particular object or group of objects, anadministrator may instruct policy controller 23 to distribute newpolicies to policy agents 139 of respective VN agents 35 of a pluralityof data centers 10. In this fashion, an administrator may manage ascalable, multi-dimensional policy framework for a plurality of datacenters. Further, each policy agent 139 may automatically apply therelevant policies without requiring the administrator to individuallymanage or update policies for each VN agent 35. Thus, the techniques ofthe disclosure may greatly reduce the complexity and simplify managementof such policies across the plurality of data centers 10.

FIG. 5 is a block diagram illustrating an example message that includestag information in accordance with techniques described herein. ExtendedBGP UPDATE message 200 conforms to MP-BGP and includes MP-REACH-NLRI 202advertising a route. For purposes of illustration, extended BGP UPDATEmessage 200 is illustrated using glyphs, rather than with packet fields.

Extended communities attribute 212 includes field 213 that defines oneor more policy rules for application to one or more objects specified byfields 214A-214N (collectively, “tags 214”). In some examples, extendedcommunities attribute 212 comprises an extended community type of“Experimental (0×80)” with a sub-type value “Tag (0×84)”. In someexamples, extended communities attribute 212 is used to carry an opaquetag value with each route.

Each of tags 214 define one or more tags comprising tag identifierswhich correspond to categories to which the objects belong. In someexamples, each tag identifier may correspond to one of an application, adeployment, an application tier, a geographic site, a virtual network, avirtual machine, an interface, a project, a security requirement, aquality requirement, a user, or a compliance requirement. For example, atag identifier of a tag 214 may correspond to a particular category, forexample, an “application” tier. Further, the tag identifier may bereferenced in a look-up table to obtain one or more definitions for thecategory described by the tag identifier, for example, a “development”application tier. In other examples, a tag identifier may be used tospecify a user, a user role, an operating system, a compute node, arack, a point of distribution, a network cluster, or a data center. Insome examples, each tag identifier is 4 bytes.

Furthermore, each policy rule 213 may further include field 215 thatdescribes one or more port range rulesets for assignment to objectsdescribed by tags 214. Each ruleset may describe specific port rangesassigned to the objects described by tags 214. Each ruleset may furtherdescribe one or more objects or groups of objects to which each policyrule 213 is applied.

An example schema for policy rule 213 of an extended BGP UPDATE message200 is provided below:[Order][Status][Port Range][Match Tags Expression]

The [Order] field describe the order of application of the policy rule.

The [Status] field indicates to policy agent 139 whether to enable ordisable the policy rule. In some examples, the [Status] field is enabledor disabled by an administrator via a user interface of policy agent139, such as a command-line interface (CLI).

The [Port Range] field indicates the port range of traffic correspondingto objects described by the tags of the policy rule.

The [Match Tags Expression] field may be a regular expression thatindicates to policy agent 139 to which objects the policy rule is to beapplied. In some examples, this action by default matches objects withina particular project. In other examples, if a user specifies a match,the default is overridden.

In this way, policy controller 23 may distribute tags to policy agents139 of respective VN agents 35 of a plurality of data centers 10 via oneor more BGP UPDATE messages 200. Further, policy agents 139 may look uppolicies corresponding to the tags and apply the policies at theinterface level so as to express the policies described by tags 214. Inthis fashion, an administrator may define simplified traffic policiesthat are scalable and robust across many different types of deploymentsand execution environments.

FIG. 6 is a flowchart illustrating an example operation in accordancewith the techniques of the disclosure. For convenience, FIG. 6 isdescribed with respect to FIGS. 1, 2, and 3.

In the example of FIG. 6, policy controller 23 assigns, to a pluralityof categories that support application workloads, tags specifying one ormore dimensions of a plurality of dimensions for the applicationworkloads (600). In this example, the application workloads are executedby one or more computing devices, such as servers 12. Further, the oneor more computing devices include the plurality of categories. Suchcategories may include applications, deployments, application tiers,geographic sites, virtual networks, virtual machines, interfaces,projects, security requirements, quality requirements, users, orcompliance requirements, for example. Each type of such categoryrepresents a dimension for workloads that generate or consume networktraffic. In some examples, policy controller 23 assigns tags to objectsthat execute or otherwise enable workloads with specific dimensionsacross multiple levels. Example levels of such objects include a globalenvironment level, a project level, a virtual network level, a virtualmachine level, and an interface level. In one example, tags map securityrequirements for the objects.

Policy controller 23 receives one or more port ranges for assignment toobjects that belong to categories described by the one or moredimensions of the tags (602). In some examples, policy controller 23receives the one or more port ranges from a user or administrator ofnetwork system 8.

For example, an administrator may specify one or more port ranges foruse by an object that belongs to a particular category described the oneor more dimensions of the tags. For example, in a productionenvironment, the administrator may specify that applications areassigned port 80 for Hypertext Transfer Protocol (HTTP) traffic. Asanother example, in a production environment, the administrator mayspecify that applications are assigned ports 20-21 for File TransferProtocol (FTP) traffic.

In another example, in a development environment, the administrator mayspecify that applications are assigned port 100 for Hypertext TransferProtocol (HTTP) traffic. As another example, in a productionenvironment, the administrator may specify that applications areassigned ports 40-41 for File Transfer Protocol (FTP) traffic. In yet afurther example, the administrator may specify that a particular financeapplication is assigned port 120 for Hypertext Transfer Protocol (HTTP)traffic. In yet another example, the administrator may specify that aspecific interface of a specific virtual machine is assigned port 150for Hypertext Transfer Protocol (HTTP) traffic. Thus, as describedbelow, policy agents 139 may use a port of a network traffic flow toidentify an object associated with the network traffic flow according tothe assigned port ranges specified by the one or more policy rulesincluded in the policy of the plurality of policies.

Policy controller 23 distributes, to respective policy agents 139 ofplurality of data centers 10, a plurality of policies (604). Each policyof the plurality of policies includes one or more policy rules. Further,each policy rule of the one or more policy rules specifies one or moreport ranges and one or more tags that specify one or more dimensions ofa plurality of dimensions that describe categories of a plurality ofobjects to which the port ranges are assigned.

Policy agent 139A of data center 10A, for example, receives theplurality of policies (606). For each policy rule of the one or morepolicy rules, policy agent 139A matches each of the one or more tags ofeach policy rule of the one or more policy rules to one or more objectsthat belong to the categories of the plurality of categories describedby the one or more dimensions of the tag (608). Further, for each policyrule of the one or more policy rules, policy agent 139A assigns a portrange to objects that belong to categories of the plurality ofcategories described by the one or more dimensions of a tag of thepolicy rule (610). In some examples, policy agent 139 stores, for eachtag of the one or more tags of each policy rule of the one or morepolicy rules, an association between the tag and the one or more objectsthat belong to the categories of the plurality of categories describedby the one or more dimensions of the tag in tag rule database 141. Inother examples, policy agents 139 may store, for each of the one or moreobjects that belong to the categories of the plurality of categoriesdescribed by the one or more dimensions of the tag, a correspondingassigned port range specified by the tag.

In some examples, policy agent 139 assigns a port range at an interfacelevel of VMs 110. In this example, interfaces 146 inherit tags fromparent objects, such as VMs 110, virtual networks, parent projects, orglobal policy sets. 10. Thus, policy agent 139 assigns port ranges tointerfaces 146 of VMs 110 by matching tags of one or more policy rulesto categories to which interfaces 146 belong.

Subsequently, policy agent 139 receives network traffic originating fromor destined to ports within the assigned port ranges. Policy agent 139identifies, based on a correspondence of source ports and/or destinationports of the network traffic to the assigned port ranges, objects thatare associated with the network traffic. For example, policy agent 139may determine that a first source port of a network traffic flow iswithin a port range assigned to a finance application. Policy agent 139may further determine one or more firewall policies that specify tags towhich the finance appliance is tagged. Policy agent 139 may apply theone or more firewall policies to the network traffic flow so as to allowor block the network traffic flow. In this fashion, policy agent 139 mayidentify an object, such as an application, associated with particularnetwork traffic based on a port address of the network traffic, andapply object-specific firewall policies to the network traffic based onthe identified object to which the network traffic is associated.

The techniques described in this disclosure may be implemented, at leastin part, in hardware, software, firmware or any combination thereof. Forexample, various aspects of the described techniques may be implementedwithin one or more processors, including one or more microprocessors,digital signal processors (DSPs), application specific integratedcircuits (ASICs), field programmable gate arrays (FPGAs), or any otherequivalent integrated or discrete logic circuitry, as well as anycombinations of such components. The term “processor” or “processingcircuitry” may generally refer to any of the foregoing logic circuitry,alone or in combination with other logic circuitry, or any otherequivalent circuitry. A control unit comprising hardware may alsoperform one or more of the techniques of this disclosure.

Such hardware, software, and firmware may be implemented within the samedevice or within separate devices to support the various operations andfunctions described in this disclosure. In addition, any of thedescribed units, modules or components may be implemented together orseparately as discrete but interoperable logic devices. Depiction ofdifferent features as modules or units is intended to highlightdifferent functional aspects and does not necessarily imply that suchmodules or units must be realized by separate hardware or softwarecomponents. Rather, functionality associated with one or more modules orunits may be performed by separate hardware or software components, orintegrated within common or separate hardware or software components.

The techniques described in this disclosure may also be embodied orencoded in a computer-readable medium, such as a computer-readablestorage medium, containing instructions. Instructions embedded orencoded in a computer-readable storage medium may cause a programmableprocessor, or other processor, to perform the method, e.g., when theinstructions are executed. Computer readable storage media may includerandom access memory (RAM), read only memory (ROM), programmable readonly memory (PROM), erasable programmable read only memory (EPROM),electronically erasable programmable read only memory (EEPROM), flashmemory, a hard disk, a CD-ROM, a floppy disk, a cassette, magneticmedia, optical media, or other computer readable media.

Various examples have been described. These and other examples arewithin the scope of the following claims.

What is claimed is:
 1. A method comprising: receiving, by a policy agentexecuted by processing circuitry of one or more computing devices andfrom a centralized controller for a computer network, a plurality ofpolicies, wherein each policy of the plurality of policies includes oneor more policy rules, wherein each policy rule of the one or more policyrules specifies one or more tags specifying one or more dimensions of aplurality of dimensions for application workloads and a correspondingport range; and assigning, by the policy agent and based on a policyrule of the one or more policy rules, a port range specified by thepolicy rule of the one or more policy rules to objects of the one ormore computing devices, wherein the objects belong to categories of aplurality of categories described by the one or more dimensions of oneor more tags of the policy rule of the one or more policy rules, whereinthe plurality of categories support the application workloads and areassigned to the one or more tags, and wherein the application workloadsare executed by the one or more computing devices.
 2. The method ofclaim 1, further comprising: receiving, by the policy agent, a pluralityof firewall policies for the objects; receiving, by the policy agent, anetwork traffic flow; identifying, by the policy agent and based on aport of the network traffic flow, an object associated with the networktraffic flow according to the port range specified by the policy rule ofthe one or more policy rules included in the policy of the plurality ofpolicies; and applying, by the policy agent and based on the identifiedobject, a firewall policy of the plurality of firewall policies to allowor deny the network traffic flow according to the firewall policy. 3.The method of claim 2, wherein identifying, based on the port of thenetwork traffic flow, the object associated with the network trafficflow according to the port range comprises: determining at least one ofa source port or a destination port of the network traffic flow; andidentifying the object associated with the network traffic flow based onthe port range including the at least one of the source port or thedestination port.
 4. The method of claim 1, further comprising matching,by the policy agent, each tag of the one or more tags of each policyrule of the one or more policy rules to one or more objects that belongto the categories of the plurality of categories described by the one ormore dimensions of the tag.
 5. The method of claim 1, further comprisingstoring, by the policy agent and for each tag of the one or more tags ofeach policy rule of the one or more policy rules, an association betweenthe tag and one or more objects that belong to the categories of theplurality of categories described by the one or more dimensions of thetag.
 6. The method of claim 1, wherein the plurality of policiescomprises at least one of: a plurality of application policies, whereineach application policy of the plurality of application policiesincludes one or more application policy rules, and wherein eachapplication policy rule of the one or more application policy rulesspecifies one or more tags specifying one or more application categoriesand a corresponding application port range; a plurality of networkpolicies, wherein each network policy of the plurality of networkpolicies includes one or more network policy rules, and wherein eachnetwork policy rule of the one or more network policy rules specifiesone or more tags specifying one or more network categories and acorresponding network port range; or a plurality of global policies,wherein each global policy of the plurality of global policies includesone or more global policy rules, and wherein each global policy rule ofthe one or more global policy rules specifies one or more tagsspecifying one or more global categories and a corresponding global portrange.
 7. The method of claim 1, wherein the plurality of categoriesincludes at least one of: an environment of a respective applicationworkload of the application workloads within a cloud data center; ageographic location of the cloud data center; a user of the respectiveapplication workload; or a compliance requirement for the respectiveapplication workload.
 8. The method of claim 7, wherein the plurality ofcategories includes the environment of the respective applicationworkload within the cloud data center, and wherein the plurality ofcategories further includes: an application environment of the clouddata center; a deployment environment of the cloud data center; or aproduction environment of the cloud data center.
 9. The method of claim1, wherein the one or more tags specifying one or more dimensions of theplurality of dimensions specify one or more of: an application of theapplication workloads; a deployment of the application workloads; anapplication tier of the application workloads; a geographic site of theapplication workloads; a virtual network within which the applicationworkloads execute; a virtual machine executing the applicationworkloads; an interface of the application workloads; a project for theapplication workloads; security requirements for the applicationworkloads; quality requirements for the application workloads;compliance requirements for the application workloads; or users of theapplication workloads.
 10. A computing device comprising: processingcircuitry configured to execute a policy agent, the policy agentconfigured to: receive, from a centralized controller for a computernetwork, a plurality of policies, wherein each policy of the pluralityof policies includes one or more policy rules, and wherein each policyrule of the one or more policy rules specifies one or more tagsspecifying one or more dimensions of a plurality of dimensions forapplication workloads and a corresponding port range; and assign, basedon a policy rule of the one or more policy rules, a port range specifiedby the policy rule of the one or more policy rules to objects of the oneor more computing devices, wherein the objects belong to categories of aplurality of categories described by the one or more dimensions of oneor more tags of the policy rule of the one or more policy rules, whereinthe plurality of categories support the application workloads and areassigned to the one or more tags, and wherein the application workloadsare executed by the computing device.
 11. The computing device of claim10, further configured to: receive a plurality of firewall policies forthe objects; receive a network traffic flow; identify, based on a portof the network traffic flow, an object associated with the networktraffic flow according to the port range specified by the policy rule ofthe one or more policy rules included in the policy of the plurality ofpolicies; and apply, based on the identified object, a firewall policyof the plurality of firewall policies to allow or deny the networktraffic flow according to the firewall policy.
 12. The computing deviceof claim 11, wherein, to identify, based on the port of the networktraffic flow, the object associated with the network traffic flowaccording to the port range, the policy agent is further configured to:determine at least one of a source port or a destination port of thenetwork traffic flow; and identify the object associated with thenetwork traffic flow based on the port range including the at least oneof the source port or the destination port.
 13. The computing device ofclaim 10, wherein the policy agent is further configured to match eachtag of the one or more tags of each policy rule of the one or morepolicy rules to one or more objects that belong to the categories of theplurality of categories described by the one or more dimensions of thetag.
 14. The computing device of claim 10, wherein the policy agent isfurther configured to store, for each tag of the one or more tags ofeach policy rule of the one or more policy rules, an association betweenthe tag and one or more objects that belong to the categories of theplurality of categories described by the one or more dimensions of thetag.
 15. The computing device of claim 10, wherein the plurality ofpolicies comprises at least one of: a plurality of application policies,wherein each application policy of the plurality of application policiesincludes one or more application policy rules, and wherein eachapplication policy rule of the one or more application policy rulesspecifies one or more tags specifying one or more application categoriesand a corresponding application port range; a plurality of networkpolicies, wherein each network policy of the plurality of networkpolicies includes one or more network policy rules, and wherein eachnetwork policy rule of the one or more network policy rules specifiesone or more tags specifying one or more network categories and acorresponding network port range; or a plurality of global policies,wherein each global policy of the plurality of global policies includesone or more global policy rules, and wherein each global policy rule ofthe one or more global policy rules specifies one or more tagsspecifying one or more global categories and a corresponding global portrange.
 16. The computing device of claim 10, wherein the plurality ofcategories includes at least one of: an environment of a respectiveapplication workload of the application workloads within a cloud datacenter; a geographic location of the cloud data center; a user of therespective application workload; or a compliance requirement for therespective application workload.
 17. The computing device of claim 16,wherein the plurality of categories includes the environment of therespective application workload within the cloud data center, andwherein the plurality of categories further includes: an applicationenvironment of the cloud data center; a deployment environment of thecloud data center; or a production environment of the cloud data center.18. The computing device of claim 10, wherein the one or more tagsspecifying one or more dimensions of the plurality of dimensions specifyone or more of: an application of the application workloads; adeployment of the application workloads; an application tier of theapplication workloads; a geographic site of the application workloads; avirtual network within which the application workloads execute; avirtual machine executing the application workloads; an interface of theapplication workloads; a project for the application workloads; securityrequirements for the application workloads; quality requirements for theapplication workloads; compliance requirements for the applicationworkloads; or users of the application workloads.
 19. A non-transitory,computer-readable medium comprising instructions that, when executed,are configured to cause processing circuitry to execute a policy agentfor one or more computing devices, the policy agent configured to:receive, from a centralized controller for a computer network, aplurality of policies, wherein each policy of the plurality of policiesincludes one or more policy rules, and wherein each policy rule of theone or more policy rules specifies one or more tags specifying one ormore dimensions of a plurality of dimensions for application workloadsand a corresponding port range; and assign, based on a policy rule ofthe one or more policy rules, a port range specified by the policy ruleof the one or more policy rules to objects of the one or more computingdevices, wherein the objects belong to categories of a plurality ofcategories described by the one or more dimensions of one or more tagsof the policy rule of the one or more policy rules, wherein theplurality of categories support the application workloads and areassigned to the one or more tags, and wherein the application workloadsare executed by the one or more computing devices.
 20. Thecomputer-readable medium of claim 19, wherein the policy agent isfurther configured to: receive a plurality of firewall policies for theobjects; receive a network traffic flow; identify, based on a port ofthe network traffic flow, an object associated with the network trafficflow according to the port range specified by the policy rule of the oneor more policy rules included in the policy of the plurality ofpolicies; and apply, based on the identified object, a firewall policyof the plurality of firewall policies to allow or deny the networktraffic flow according to the firewall policy.